Publication Year

2018

Publisher

International Whaling Commission

Abstract

Four previously documented surveys focusing on satellite tagging Arabian Sea humpback whales (ASHW) have taken place off the coast of Oman since 2014. We present information of the most recent multidisciplinary survey from November 2017 including results of telemetry studies to investigate spatial ecology, photo-identification work to support population estimates and the trial of new methods using Unmanned Aerial Vehicles (UAV) in conducting non-invasive health assessments. The findings document the first record of the transoceanic passage of an ASHW within the Arabian Sea and preliminary evidence of regional scale connectivity. Small vessel surveys resulted in 45 hours of effort resulting in a total of 35 sightings and encounters with over 18 identified individual ASHWs. Five tags were successfully deployed, three being attached to to whales already identified in the ASHW catalogue (one female and two males) and two whales new to the catalogue (of as yet unknown sex). The recent telemetry work brings the project total to 14 deployed tags. Four whales from the recent tagged group occupied regions previously described as important habitat in the South of Oman including the Gulf of Masirah and Hallaniyats Bay. The tag with the longest tracking duration (n=120 days) documented the passage of an adult female from the Gulf of Masirah across to the west coast of India, south towards to the Gulf of Manar off the southern tip of India and the subsequent return of the whale to the tagging site. Additionally, a hexacopter UAV (drone) was used to acquire digital images of 6 whales to inform investigations into body condition (length-width relationship), tissue scaring and skin disease. UAVs that were flown through respired condensate (blow) resulted in collection of three viable samples collected for micro-biome assessment of the respiratory tract. On a broad geographic scale the tracking data continues to confirm the importance of waters over the continental shelf in southern Oman for ASHW and together with passive acoustic monitoring studies provides new evidence to support previous understanding on the connectivity between humpback whales of the Arabian Sea. The frequency of sightings in the study area, and documented breeding related behaviour during the survey supports existing evidence demonstrating that the Gulf of Masirah is a critical habitat for the ASHW. Effective conservation of this population requires concerted application of threat mitigation, whilst studies continue to support the on-going conservation management requirement to understand the broader spatial ecology of the population.